What approaches are there to apply AI to global economic processes?
It's currently just too complex
The different sources of information are too varied, in economics this is often referred to as a local knowledge problem, which hampers many large scale plans. Humans can react to slight differences like respecting local traditions, landscapes, history but an artificial intelligence would (currently at least) struggle not to generalise over such a large scale as a whole country's economy.
The real work in this case (and actually most 'AI' tasks) would be collecting all the necessary data. Here that part job is currently insurmountable.
Currently a human lead planned economy would do a better job.